1. Field of the Invention
The present invention relates to a magnetic resolver for detecting the rotation angle of a rotor.
2. Description of the Related Art
Conventional magnetic resolvers generally include a rotatable rotor core, a stator core, with two stator plates that sandwich the rotor core from above and below and that have convex, protruding poles arranged along the circumference of the stator core, and thin-film coils that are wound around the respective protruding poles of the stator core, and that detects a rotation angle of the rotor core by using the fact that the inductance of a coil varies with the rotation angle of the rotor core (see, Japanese Utility Model Application Publication No. 5-3921 (“JP-5-3921”), for example).
In a conventional resolver as described above, in which the film-shaped coils are used that are formed on a substrate in a pattern, it is possible to realize a thinner resolver body as compared to a conventional resolver in which wire is wound around the concave cores on a stator that are faced toward a rotor in the radial directions. In addition, it becomes unnecessary to wind wire to obtain coils. However, Japanese Utility Model Application Publication No. 5-3921 fails to disclose a specific configuration of a substrate on which the film-shaped coils are formed. If the substrates of the film-shaped coils are individually provided for the respective protruding poles, assembly is difficult. In addition, when the film-shaped coils are used, it is more difficult to easily increase the number of windings of the coil, as compared to a conventional resolver in which wire is wound around the cores on a stator that are faced toward a rotor in the radial direction.
In this type of variable reluctance (VR) resolver, what are important to efficiently enhance the resolution and accuracy of detecting the rotation angle are that the range of the variation of the magnetic resistance that accompanies the rotation of the rotor is large, and that the mode in which the magnetic resistance varies with the rotation of the rotor is smooth and stable. The mode in which the magnetic resistance varies with the rotation of t the rotor mainly depends on the configuration of the rotor core and the configuration of the protruding poles (including the relative relationship therebetween).
With this regard, although a specific configuration of the profile of the rotor core is described in JP 5-3921, none of the form of the protruding poles, the relationship between the form of the protruding poles and the form of the profile of the rotor core, and the positional relationship between the protruding poles and the periphery of the rotor core is disclosed. Accordingly, there is a lack of information to efficiently enhance the resolution and accuracy of detecting the rotation angle.